Concurrency
by Elfpen
Summary: After more than fourteen hundred years of waiting for Arthur, a friendship with a University student flings Merlin back into his days at Camelot. When the Once and Future King finally returns, the adventures of old are begun anew. But new beginnings are often rocky, and getting Arthur back on his feet in this new world proves to be just as daunting as it was the first time around.
1. Chapter 1

He liked to think that it was a nice place. A bit unkempt, perhaps, but he preferred it that way. Hidden back in a copse of trees a ways away from the rest of the town, it was somewhere between a cottage and a house, but for all purposes, looked like a burrow. That last bit was mostly his fault. The only reason the structure had lasted so long on its own was because he slapped a spell on it every time it looked fit to keel over, but even with a keeper around to look after them, the oak and plaster liked to complain of old age often. The exterior had become friends with the local foliage, and the two had grown quite literally inseparable over the years. The south wall had been having an affair with a hedge of English ivy for the last few centuries, and the weathervane had eloped with a thunderstorm some years ago, though he couldn't remember exactly how long it'd been gone.

Although he thought the interior was in better shape, in actuality, if someone were to ever step foot in his home, they'd have a game of finding their way about. They would trip over books, and bump their heads on floating contraptions, ask about the odd and eclectic décor, and probably comment on how the entire house was a giant fire hazard just waiting to be turned in to the marshal. But he wouldn't care either way. It wasn't like he would let it burn down, and he knew his way around, despite the mess.

It was a decent size, and warm. In his mind, he often compared it to what that talented young Tolkien had once penned, a 'hobbit hole'. Perhaps it wasn't below ground, but it was rich with the shine of stone tile, the smell of paper, ink, and age, and steeped in the history of centuries past. The front door was not round, but it was a handsome green, with (last he checked) a nice brass doorknocker that was never used. The front room was home to various weapons and bookshelves, and had an umbrella stand that doubled as a place to keep swords and staffs. Past that, the living room was well-lit with windows and a cozy fireplace. It had a TV, a dvd player propped up by numerous spellbooks, and a coffee table that was now made up of just as much coffee as it was table. The couch had one leg that had been gnawed off by a beaver and now sparkled with the fifty-year-old suspending spell he'd put on it to hold it up. It's upholstery had once been blue, but was now a strange grey color. It was covered in half-read paperbacks, over half of which were Terry Pratchett novels.

His study was cluttered, but not necessarily messy, and contained some of his most important belongings. Sixth-century manuscripts sat shelved alongside printed internet articles and Wikipedia pages in an old Victorian writing desk, while his MacBook took up residence in his leather armchair. He'd hung an old Welsh Red Dragon across one wall, but over time it'd become construed by a wildly growing book pile in the corner. The kitchen was the cleanest room of the house. He kept less food than he needed and more tea and coffee than he could want, and somehow it balanced out perfectly. The chairs at the table were mis-matched by a century or two, and the refrigerator's continued operation was a miracle in and of itself, but he didn't mind. The gas stove was usually roasting a kettle and the electric lights had stayed on for years at a time as an unsleeping guardian of the house.

But by far the most familiar sanctuary of his house was his bedroom. It was the only second-story room of the entire house, and contained the oldest of his possessions. He had modern conveniences, of course: a soft mattress, an alarm clock, an electric light and a space heater. But there were also the memories of his old life: Gaius' old medic kit and potions shelf, a necklace belonging to Guinevere, Gwaine's sword, Arthur's cloak. They each had their place, and he kept them clean and preserved. Years ago, they would have only caused him pain, but he'd learned to look upon them fondly. They were reminders of the long gone, and the soon to come.

Presently, a sharp kettle whistle brought him off his bed, where he'd been re-reading _The Hobbit_ for perhaps the fiftieth time. He navigated the spiral stairs with ease, despite the fact that most of the steps were covered with stacks of clean laundry and dvd cases. He poured a pot of Lady Grey and left it to steep while he put together a tray of jam and biscuits. As he did so, the calendar sitting on the counter caught his attention.

_September 2,_ it read. He felt surprised. His birthday? Already? He glanced over at the top of a chalkboard that peaked out from behind his askew coffee maker. He set it back to rights so he could see the year-old inscription there.

_1420_

He hummed discontentedly to himself. He always hated it when he had to ruin a perfectly nice, round number like this. _Ah well,_ he thought. _A decade more and it'll be nice and round again_. He smudged off the end of the inscription and rechalked it.

_1421_

Nodding to himself, he took his tray of tea into the living room and set it down on the table amongst a few other dirty tea cups and a stack of old cassette tapes that he still wasn't sure what to do with. He sat down with a sigh and looked across at his TV. For a moment before he turned it on, he could see his own reflection in the dark screen. He looked hardly a day older than he had fourteen hundred years ago, save for a little more stubble on his cheeks and the switch from tunic and neckerchief to a pullover jumper. It been about three centuries since he cared about hair combs, and at that moment, it looked as if a cow had tried to eat off of his head. He sighed and turned on his TV with a glance. He'd lost the remote decades ago, but had found that magic worked just as well. Immediately, the history channel came into focus, running some programme on the lives of the Tudors. Merlin hunkered down with his tea and squinted at the screen. One of his favorite pastimes since the invention of the television was watching bad historical documentaries and keeping tally of all the things they got wrong. On a few occasions, he'd written letters to the producers and editors, and had specifically left out his name and address. He'd gotten a few apology letters with promises of correction, but more often than not, his letters were ignored. He sniffed at his tea and frowned. Perhaps he really was becoming an old cynic.

It was only true; sixteen centuries certainly qualified him as 'old', but Merlin had been working hard to keep cynicism at bay for a while. He prided himself on his lasting physical youth, and tried to not let go of the vitality and optimism that he remembered possessing in his fargone life in Camelot's heyday. To stave off boredom and depression, he'd taken to becoming a scholar. He'd lost count of how many college degrees he'd earned over the years, but did enjoy the occasions where he could demand that people call him _Doctor_. He was fluent in several languages now, in addition to the English and Old Tongue that had stayed with him all his life. He travelled very occasionally, but never often enough to keep him away from Avalon, where he lived patiently across the banks. He visited the town center often, and had a particular fondness for vising the local bookstore as well as, on occasion, the daycare. With age, Merlin found, came a certain need for childlike company. There was something in young minds that he missed in himself, nowadays. He'd held a whole spectrum of jobs over the years, but could never stay in one profession for long, else people would begin to notice. Notice how he never aged, notice how his personal records were limited or faked, notice how he just _knew_ things, notice how he had done and seen more than any man his age ought to have. Sometimes, he didn't mind if people noticed, it amused him. But attention was dangerous for him. Most times, he would mournfully leave a memory charm on those he'd grown attached to. It was better that way.

But then, once in a very long while, a spark of something else would come into his life. Apparently, as a rather surprised Merlin had learned centuries ago, there were still sorcerers left living in the world. In fact, there were quite a few of them, living in tandem with and hidden from the rest of the world – _muggles_, his folk called them. And apparently, these magic folk had stories about him, fables and tales, and heroics and legends. He was almost embarrassed about it. But none of them believed that he was still alive. Well, _almost_ none of them.

That's how he'd met William Creyder.

It took Merlin longer than he'd ever admit before he'd realized that he had a stalker. Naturally, Will would've denied any claims to stalking, but semantics didn't change the fact that he'd been following, staring at, researching, and watching Merlin from a distance for the better part of a year when Merlin finally noticed.

And _notice _might be better translated into _was ambushed._ 'Ambushed' was more literal than one might expect.

He'd been sitting at the local coffee shop, minding his own business, when very suddenly, there was a man seated across from him. He'd jumped at the sight of him.

"Ahhh…. Hello," he'd said uncertainly, twisting his eyebrows in confusion.

"You're _him_, aren't you?" The man asked. Merlin frowned and looked him up and down. Young, probably a university student. Hoodie, coat, rucksack. He looked fit, but carried a bit of extra weight in his face and around his middle. He had short dark hair, big brown eyes, and perhaps lowest facial ability to conceal a lie that Merlin had ever seen.

"I'm… _who_, exactly?" Merlin asked. The man across looked nervous.

"Merlin," the man whispered.

Merlin frowned, face growing serious. "That's my name, yes, what of it?" he snapped.

"No, but," the boy was obviously flustered, "I mean… you're _Merlin._ _The_ Merlin." He looked around and whispered, "You're _Emrys_."

Merlin stared for a moment, then darted out his hand and grabbed the boy's wrist hard. He could feel his magic welling up defensively – little did he know, the other man could feel it, too, which was a major factor in his expression of fear.

"I don't take to attention lightly." Merlin growled, "Who are you?"

"W-Will," the man stuttered. "My name's Will. Please, I'm sorry for startling you, I just-"

"You just _what?"_ Merlin tightened his grip, glaring. There had only been a handful of times in his life when people figured out who he was without him telling them first. Most of them were out to either unmask him to the world or capture his power. He'd learned his lesson in dealing with them long ago. Will gulped and glanced down at the man's white knuckles around his arm.

"I-I'm… I'd wondered for a while, never thought that you'd actually…" the hand tightened. He blurted, "I'm a squib."

That gave Merlin pause. He frowned, and let his hand go somewhat limp. "You're a _what_?" he asked.

"A-a squib," Will said, not meeting his eyes. "My parents were magic, but I'm-"

"You're from a _magical_ family?" Merlin's browline shot up.

"Yes, but I'm-"

"You aren't from that damned Ministry, are you?"

"No, no no, I just live here, really, I do, I go to Uni here."

"University? I thought you'd have gone to that what's-it school up in Scotland?"

"I don't _have magic_," Will said, blushing like it was a sore spot, "please, I don't mean any harm, truly I don't." Merlin stared at him some more, and for a tense second neither of them moved. Eventually, convinced by the sheer terror and clarity of the boy's expression, Merlin sighed, released his arm, and sat back in his seat, his face melted into a much more civil expression.

"Right then, Will The Squib, what interest does a boy like you have with an old cocker like me?"

Will was fighting a shaky smile, perhaps because Merlin didn't _look_ like he could be much older than Will himself. "W-well, I… I've just… I've seen you about here, before. I know that most people don't think you're…" He looked up nervously, like Merlin might be offended, "around anymore," to which Merlin allowed a small smile, "but… I just… I wondered, is all."

"Wondered if I was still kicking?"

"No, no no, I've always thought that," Merlin's eyesbrows rose again. "I just wanted to know if you, were, you know, _actually him_."

Merlin nodded, and rubbed his stubble sagely. "Okay," he said, and sipped at his coffee. He looked up and across at the barista with a sweet expression.

"Kate, could you get a cuppa for my friend, here?" The barista smiled at him. "Right off, Dr. E – on your tab, too?"

"Sure." He turned back to Will. "I should apologize for my behaviour. Your one of a few who's ever figured it out, and most of those don't mean me well."

Will was beginning to smile a bit. "_Doctor E?"_ he had to ask.

"It's not a lie, I _am_ a doctor," Merlin said defensively, "several times over, in fact." At Will's surprised expression, he added, "did you expect me to lie around wallowing in my hermitage all this time? I'm familiar with the University life." His eyes suddenly drifted and he frowned at a memory. "Speaking of which, I suppose I ought to get back with Dr. Brachnell," He muttered. Will's eyebrows role.

"Dr. _Brachnell_?" Will asked, "the Uni President?"

"Yes," Merlin said slowly, "he's been on my back about a full time position for nearly a decade – even before he became president. I told him I only adjunct, but he won't listen."

"You teach at my university?"

"A class here and there, yes. But not much. Suits and robes aren't my taste."

Will laughed. "I don't blame you," His smile was lopsided. Kate came over with a steaming cup of tea and a small shot of milk and placed it front of Will.

"Anything else, Doctor?"

"No, thank you, Kate," Merlin smiled up at her.

As Will, stirred sugar into his tea, Merlin studied him. There was something in Will's honest expression and inability to conceal his emotions that brought up a certain fondness in Merlin, usually garnered by only his close friends.

When Will looked up and saw Merlin watching him, he blushed. "Sir?" He asked uneasily.

"You know, I think I like you, Will The Squib." Merlin said as he swirled his coffee cup. "You remind me of someone." He drank the last of his coffee, and set it off to one side. In a sudden movement, he began donning his coat and grabbing his messenger bag. "It's a pleasure to meet you, but I have to be off home now. Phone calls to make, teaching positions to decline, documentaries to overanalyze." He flipped up his coat collar and wound a scarf about his neck.

"Oh, but… eh, Sir-" Will stood, surprised by Merlin's sudden departure. He blinked a few times, realizing all at once that he'd met his hero but failed to actually talk with him, "I wanted to ask you, I mean… could I call you, or could you give me your-"

"You misunderstand me, Will," Merlin rounded on him, voice authoritative, "I said I like you. I never said I trust you." He let the disappointed expression sink into Will's face, but then he nodded at the table where the boy's tea still sat and adjusted his voice with a kinder tone. "However, I do come in here every Tuesday afternoon, if you're desperate for bad company. Now, warm up, study well for class, and pretend for all the world that we never met, alright?" He headed for the door, but not before he told Kate, "give him what he wants on my tab." Kate nodded and eyed Will. The bell on the door rang as Merlin left.

Will was left sitting at the table, sipping his tea absently. His heart was racing. It_ was_ him. It was really him – _Merlin Emrys_! He wondered if he should be happy or terrified.

"I didn't think Dr. E taught at the University anymore," Kate said when she came to collect Merlin's empty mug.

"Oh, he doesn't," Will smiled.

"If you're not his student, then, how do you know him?" She nodded at the door. "Bit of a recluse, I never see him with company in here. You a friend of his?"

Will shrugged with a tiny smile. "Something like that," he said, hoping.

* * *

**A/N:** Right, I have only a vague notion of where this story is headed, so bear with me. I've been playing around with multiple reincarnation/post-finale fic ideas, and this is one of many. I know Will is an OC, but I thought it necessary to make it clear that Merlin and Arthur aren't the _only_ones in existence. Merlin should have modern-day friends who know who he is, I think. Arthur will come along in the story later, as should some other familiar faces. As far as plot goes, I'm still working on it.

Oh, and be assured, there will be plenty more nods, references, and flat-out crossovers from _Harry Potter_ along the way, but I don't intend on making them a huge focus, more like a happy coincidence. Also, some finer points of historicity will, of course, be altered from real life. But we'll get there when we get there.

If you've read this, I hope you've enjoyed it! I'll try to figure out another chapter sometime soon.


	2. Chapter 2

A/N:Wow! I was _not_ expecting this kind of response! Thank everyone so much for your reviews, and I'm really excited that you guys are enjoying my rendition of future!Merlin so far. Hopefully, I'll do justice to your expectations!

* * *

And so it was that every Tuesday afternoon, sometimes a little late, sometimes a little early, Will would haul a new week's worth of homework down to the old end of town, and find his way to the door of Hoffi Coffi, Merlin's preferred coffee bar. Sometimes they'd talk, sometimes they wouldn't. A time or two, Will found himself receiving a personal class session when one of his simple questions awakened the professor hidden within Merlin's vast memory. He got help on his homework and lessons on dead languages, and sometimes a suspiciously detailed account of times long gone.

Will didn't mind. Neither did Merlin, after a while. He was stiff-backed and stiffer-lipped for the first few weeks, but in time, Will saw him relax and loosen his frown, let his shoulders fall comfortably in Will's presence even as the younger man studied his every move. Somewhere between the coffee and coursework and reading (for if Will had his homework out, Merlin was sure to have a paperback on hand as well – the title changed every week, Will had noticed) they found time to talk, about everything and nothing in particular.

They spoke of Will's family only once, briefly. He relayed how his parents were both employed by the Ministry (Merlin grimaced) and how his brother made wands, how his sister's brains were the pride of the family, and how being the youngest of three and the only one without magic to boot was, to put it lightly, difficult. Merlin looked sympathetic by the end, but only for a moment, after which he steered the conversation away kindly. They never spoke of Will's family again.

Instead, they spoke of school, of university, of films and television dramas, of books and the classics, of their favorite sports, and interesting or amusing articles they'd read on the internet. Once, Will had been brave enough to ask after the accuracy of the Arthurian legends he'd been learning in school. To his slight surprise, Merlin indulged him without trouble. He spoke of the exaggerations of Lancelot's affair, and spent quite some time correcting all misconceptions about Guinevere. She must have been close friends with Merlin, Will gathered. He spoke of the Round Table and of Mordred, before Will at last asked, "And… why is it that everyone seems to remember you as a skinny old man with a long white beard?"

Merlin scoffed and tossed his head back suddenly. When he looked back up, his face was the embodiment of annoyance. Will tried not to laugh at the sudden outburst.

"That was, what, three, four times? So I needed a disguise, and used an aging spell. Somehow, that's all anyone ever remembers about me." He shook his head. "Flattering," he spat sarcastically. "It's all that damned Geoffrey's fault, I'd bet you a tenner."

"Geoffrey?" Will asked.

"Monmouth."

Will's brows rose. Oh, of course. _That_ Geoffrey. Naturally.

"I ought to have put that trim little beard of his down a shredder. But of course we didn't have shredders in Camelot, and oh damn, I've gone and made myself feel old again." He sighed and shook his head. "but what the hell, I'm ancient." He ordered a beer after that.

Will had actually forgotten several times just how old Merlin was. Yet, the man's history was so fascinating, Will couldn't help himself but to ask more and more about Camelot. Merlin obliged kindly, but somehow in his excitement, Will forgot just how close to home this all must've been hitting the other man, and ended up asking after Arthur. Merlin seemed unfazed at first, and continued easily, but about half way through his third story, he'd slowed to a halt and begun to stare into space with a sad expression. When he came out of his trance, he heaved a sigh before downing a whole beer in three massive gulps.

Will was mortified, and gave his apologies by keeping silent on all things Camelot for the following weeks.

Autumn leaves clattered away in cold winds, and the locals brought out snow shovels and heavy coats as Winter took her turn. By mid-December, Will was on break from Uni, but he remained in-town, (Much to Merlin's surprise:_"Ought you not got somewhere to go for Christmas, Will?" "No. Family Christmases are always… dull." "Oh.")_ so he kept up his habit of sitting with Merlin to read and drink and talk well past dark, every Tuesday, always huddled in the same back booth of Hoffi Coffi.

Will had asked Merlin about that name, 'Hoffi Coffi' once. Merlin had smiled and replied merrily,

"Cymraeg."

"What?"

"It's Welsh," he clarified.

"Oh. What's it mean, then?"

"To like coffee."

A bit of an anti-climax, Will thought, but it did explain a thing or two. For one, why he could never pronounce the shop owner's name correctly, and two, the strange code Merlin often spoke with Katie whenever he first came in.

"Prynhawn da, Merddyn," she'd say, and he'd smile at the old name she used for him.

"Prynhawn da. Sut dach chi?"

"Yn dda iawn. A chi?"

"Wi'n braf. Ga i yn coffi?"

"Wrth gwrs." She'd make him the same coffee he ordered every week and hand it over with the bright smile of someone who didn't get to speak in her native tongue often. He would smile back with the look of someone who was happy to oblige the favor.

"Diolch," He'd nod, drop a fiver on the counter, and take his coffee back to the booth.

"Croeso."

As he sat down, Will would glance at Katie and then Merlin. "Where you ordering coffee, flirting, or both?" He'd ask with a smile.

Merlin would laugh. "You ought to be ashamed of yourself. I'm a millennia and a half older than her, at least."

"She doesn't know that."

Merlin would snort into his coffee and shake his head. "Perhaps not, but I'm already spoken for – have been for a long time." He'd say it with a wistful tone, and Will would let the subject drop.

It was moments such as these when Will remembered just who Merlin was, how long he'd been around, how much he'd seen and learned. Languages, memories, lifetimes of untold history. The more Will learned about the man, the more he wanted to get to know him better.

Which was why he was so disappointed one Tuesday night, when Merlin finished his latte and announced, "I won't be here next week, I'm afraid."

"What? Why?" Will asked, perhaps too quickly.

"Oh, don't look so glum, you squib," Which had become a friendly name for Merlin to use, "I'll see you around, alright?" And, coming from Merlin's mouth, it didn't sound so much of an escape route as it did a promise.

"Pob hwyl," Merlin tossed back at Katie as he left. Merlin hadn't yet taught Will enough Welsh for him to remember what the words meant, but it sounded to him like an abrupt goodbye.

* * *

Perhaps if he'd thought about it, Will could've realized in advance why Merlin wouldn't be up for coffee the following Tuesday – It was Christmas day. Will had only realized this himself when he showed up to Hoffi Coffi at the normal time (despite Merlin's not being there, he was beginning to suspect his own growing dependency on the place) only to find the doors locked shut with a jolly window drawing of St. Nick wishing them the happiest of Christmas, presumably with coffee found elsewhere. After heaving a sigh that fogged on the window, Will turned back around and waited for the bus that would take him to his flat.

* * *

He was looking down as he climbed the steps to his front door, digging through his rucksack with frozen fingers to find his keys, so it was at least moderately understandable when he didn't see the man standing there.

A muffled _oomph_ noise preceded a scuffle and wooden tapping noise, and Will was just looking up to snap off at the strange man at his door, but then, between the thick woolen scarf and a tweed flat cap, a dimpled smile.

"Merlin? What the hell are you doing at my flat?!"

Merlin laughed. "Happy Christmas to you too, squib. You said you hadn't any company for Christmas, I thought I'd help."

Will's expression softened, but he shook his head. "That's nice of you, Merlin, but… I'm not really ready to have visitors – place is a mess, not even a spare box of tea left."

Merlin chuckled. "Yes, well, I think _I_ have one or two."

Will looked up at him, puzzled, "What, you just… carry them around, do you?"

"No, that would be ridiculous. Come along, then," Merlin put a hand to Will's back and steered him back around toward the steps.

"What-where are we going?" Will looked up and down at Merlin, noticing for the first time the wooden cane that Merlin was leaning on whenever he stepped on his right leg. "And what's happened to your leg?"

"Creaky old bones, I'm afraid. Ancient injury still likes to torment me, cold makes it worse. As for _going_, the car's down there." Merlin paused just a tick to gesture with his cane down towards the street, where a decades-old mini cooper blended into the background, it's miss-matched blues and greys looking a bit in need of a wash.

"Your car?" Will asked.

"Her name is Mollie. Not much to look at, but a good heart in her. And it's freezing out here, so for god's sake, get in."

"But… where are we _going_?"

Merlin already had the driver's side door open and had tossed his cane in. "My house, of course. I told you, I have tea. Also, unless it's decided to burn the whole place down, there's a Christmas bird in my oven that should be cooked by the time we get there. Or did you have other plans?"

Will blinked, drew breath to protest, but then let it out in a huff. If he'd had a mirror, he might've been able to see how completely baffled he looked in that moment. Christmas – Christmas dinner, with Merlin Emrys. No big deal. Of course not. What the hell, they'd been having coffee and biscuits and impromptu Welsh lessons for the past two months. And now Merlin was inviting him to his house – wait, Merlin had a _house_?

Lords, what would his family say?

Shrugging, and feeling a smug sort of grin rising, Will rushed forward and climbed into Mollie's creaky passenger seat. And then, they were off.

* * *

A/N: Alright, the bit with the Welsh I just couldn't help. I'm taking an introductory Welsh course this semester, and figured that if I could put it to use anywhere, it'd be somewhere in my Arthurian-themed stories. So there you are. Hopefully I've gotten all the grammar right.

It's a short chapter, but I hope y'all enjoyed it nonetheless!


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